The present invention relates generally to a method for dispensing laminations of many different shapes and sizes (i.e, E and I lams, motor lams, LTL ballast lams, etc.), as well as to a lamination dispensing apparatus, and more particularly to a more efficient apparatus that dispenses a predetermined stack (amount) of laminations from a string (supply stack) of laminations. Typically, the dispensed laminations will be used for forming the core of a transformer.
Known lamination dispensing machines are used in a process to form conventional transformers with a bobbin that holds a wire coil and terminals, which are secured to a core. The core is typically formed in two parts, with each part being formed by using a stack of a predetermined amount of flat laminations. In some conventional cores, an E-shaped part containing a stack of E-shaped laminations (hereinafter xe2x80x9cE-lamsxe2x80x9d) is mated with an I-shaped part containing a stack of straight bar laminations (hereinafter xe2x80x9cI-lamsxe2x80x9d) to complete the core. Prior to joining the E-lams and the I-lams, the center bar of the E-shaped part is extended through an aperture in the center of the bobbin. Then, the I-shaped part is welded in two places from the top and bottom distal ends of the E-shaped part, thereby securing the bobbin to the core.
In the conventional lamination dispensing process, a string (supply stack) of commonly shaped laminations are received by a dispenser which is used to count or measure and remove a predetermined stack (amount) of laminations from a string (supply stack) of laminations, where the predetermined stack of laminations removed corresponds to the height of the core. Removing the predetermined stack of laminations is accomplished by moving the string into a position to engage a reciprocating block, or other member, that abuts only the predetermined stack of laminations to thereby remove them from the string. A bar or pressing arm attached to an actuator and the block engages an edge of the laminations, and thrusts the predetermined stack of laminations away from the string. This separated stack of laminations is then moved either by hand or by machine to a location to be assembled with the bobbin and the other half of the core.
In this conventional dispensing machine, however, the friction between the laminations in the stack and the remainder of the string causes the laminations that remain in the string to fan out (instead of maintaining a perfectly aligned separation) when the stack is being moved. Specifically, the uppermost lamination that is being moved by the block is in contact with the lowermost lamination of the remainder of the stack (which is intended to remain stationary). The friction between the surfaces of the moving lamination and the remaining xe2x80x9cstationaryxe2x80x9d lamination causes the xe2x80x9cstationaryxe2x80x9d lamination to move slightly in the direction of the motion of the block. This can start a chain reaction that moves other laminations in the remainder of the string, causing the fanning out of these laminations.
Once the laminations are fanned out, moving the stack into position to be separated from the string, or moving the block to press against the stack, either causes the machine to become jammed or causes the incorrect amount of laminations to be moved. The time taken to unjam the machine lowers productivity, and the incorrect amount of laminations in a core reduces the quality of the transformer and/or raises expenses.
Thus, it is an object of the present invention to provide an improved lamination dispensing machine that raises productivity and provides a product of high quality.
More specifically, an object of the present invention is to provide an improved lamination dispensing machine that prevents jamming of laminations, and more consistently dispenses the correct amount of laminations.
An additional object of the present invention is to provide an improved lamination dispensing machine, as well as an improved method of dispensing laminations, that prevents fanning out of the laminations in a string while a predetermined stack of laminations are being removed from the string.
These and other objects of the present invention are discussed, or will be apparent, from the following detailed description of the invention.
In keeping with one aspect of the invention, a lamination dispenser is provided for dispensing a predetermined stack (amount) of laminations from a string (supply stack) of laminations. Each lamination has an outer edge with a first area of the outer edge opposing a second area of the outer edge. A third area of the outer edge is perpendicular to the first and second areas of the outer edge. The dispenser also comprises an ejector for removing the predetermined stack of laminations from the stack by pressing against the third areas of the predetermined stack of laminations. A retainer mechanism is provided for the dispenser for exerting pressure against the outer edge of at least one lamination adjacent the predetermined stack of laminations while the ejector moves the predetermined stack of laminations. The pressure is sufficient to secure at least the adjacent lamination in place. Preferably, the retainer mechanism simultaneously applies the pressure to both the first area and the second area of the adjacent lamination or laminations.